AIDS continues to represent a critical issue for society. Despite significant developments on many fronts, the somber morbidity and mortality statistics remain. Intravenous drug abusers (IVDAs) comprise the second largest risk group and play a singificant role in the prevalence of AIDS among adult females, the pediatric age group, and New Yorkers. Even more devastating is the significance of intravenous drug abuse in the prevalence of AIDS and AIDS-related disorders among minorities. Blacks and Hispanics experience a frequency of AIDS cases disproportionate to their population distribution. More importantly, the best predictor of AIDS in minority women and children in the northeast is the distribution of heterosexual IVDAs. As an extension of its concerns of the implications this holds for the nearly 2,1000 patients under its care, the Addiction Research and Treatment Corporation (ARTC) proposes a three-pronged epidemiologic study. The first component is a three year assessment of the post-HIV infection clinical course, utilizing markers of immunological function, in predominately Black and Hispanic IVDAs. The second component is a HIV seroprevalence study of the sex partners of intravenous drug abusers assessing for those risk factors in the IVDA and their sex partners most greatly associated with HIV seropositivity. The final component is a three year prospective seroconversion study of those sex partners of IVDAs, who have as their only HIV exposing behavior a sexual affiliation with a HIV seropositive IVDA also enrolled in this study. This will allow an assessment of those risk factors associated with the sexual transmission of the HIV virus. This project builds upon the prior work of this research team and will enhance the risk reduction efforts of this organization.